This application claims the priority of German Application No. 100 39 913.4, filed Aug. 16, 2000, the disclosure of which is expressly incorporated by reference herein.
The invention relates to an arrangement for the relative angle-of-rotation adjustment of a camshaft of an internal-combustion engine with respect to a driving wheel having an interior part which is non-rotatably connected with the camshaft and which has at least approximately radially extending blades, a driven cell wheel which has cells which are distributed along a circumference, are bounded by webs and can be divided into two pressure spaces by the blades guided in the cells in an angularly movable manner, during the admission or discharge of hydraulic pressure to or from the pressure spaces by way of control lines, the camshaft being rotatable by way of the blades between two end positions relative to the cell wheel, and at least one locking device which is operative between the interior part and the cell wheel whereby the interior part can be locked with respect to the cell wheel in at least one of the end positions.
From German Patent Document DE 196 23 818 A1, an arrangement of the above-mentioned type is known, in which, by means of a locking element arranged in the rotor of the camshaft adjusting device, the camshaft adjusting device can be locked in an end position. The locking element constructed as a locking bolt is disposed in the rotor of the camshaft adjusting device and can be displaced parallel to the axis of rotation of the rotor. By way of an opening arranged in the stator of the camshaft adjusting device, the locking bolt can be changed into its locking position. The construction of this locking device requires relatively high expenditures. The locking device also requires a highly precise fit, so that the locking bolt can be changed into its locking position in a secure fashion.
It is an object of the invention to improve an arrangement of the above-mentioned type for the relative angle-of-rotation adjustment of a camshaft with respect to its driving wheel such that a simple, operationally reliable locking unit for a camshaft adjusting device is created which has few additional components.
According to certain preferred embodiments of the invention, this object is achieved by providing at least one of the blades of the interior part with a head part having at least one locking element which interacts with a locking structure of the cell wheel and is changeable as a function of operating parameters from a locked position into an unlocked position.
The locking unit according to certain preferred embodiments of the invention is distinguished by a simple construction, in which a reliable locking unit is created in a simple manner particularly by a modification of the already existing components. At least a portion of the operating forces required for the unlocking can be applied by the centrifugal force generated during the rotation of the camshaft. An assisting hydraulic unlocking force is implemented in a simple manner by a hydraulic line leading to the blade element of the interior part. As a result of the admission of pressure to the hydraulic line, the radially longitudinally displaceable head part of the blade can be changed against a spring force from a locked position into an unlocked position.
A certain preferred embodiment of the invention is explained in detail in the following description and in the drawings.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.